Group membership is a strong driver of everyday life in humans, influencing similarity judgments, trust choices, and learning processes. However, its ontogenetic development remains to be understood. This study investigated how group membership, age, sex, and identification with a team influenced 39- to 60-month-old children (N = 94) in a series…

Recent research has shown that infants are more likely to engage with in-group over out-group members. However, it is not known whether infants' learning is influenced by a model's group membership. This study investigated whether 14-month-olds ("N" = 66) selectively imitate and adopt the preferences of in-group versus out-group members.…

Study goals were to explore whether children clustered into groups based on reactions to witnessing bullying and to examine whether these reactions predicted bullying intervention. Seventy-nine children ("M" = 10.80 years) watched bullying videos in the laboratory while their heart rate (HR) was measured, and they self-reported on…

Five- to 13-year-old European American children ("N" = 76) predicted characters' decisions, emotions, and obligations in prosocial moral dilemmas. Across age, children judged that characters would feel more positive emotions helping an unfamiliar child from the racial in-group versus out-group (African American), happier ignoring the…

"Interpersonal" rejection and "intergroup" exclusion in childhood reflect different, but complementary, aspects of child development. Interpersonal rejection focuses on individual differences in personality traits, such as wariness and being fearful, to explain bully-victim relationships. In contrast, intergroup exclusion focuses on how in-group…